地球重力模型及中国大陆重力场的计算

融多颗卫星数据、地面重力值和其它资料一起的地球重力模型EGM 96 ,为研究中国大陆的重力场及相关问题提供了一个高精度 36 0阶的球谐系数。在分析EGM 96的基础上 ,计算并简单解释了中国大陆的自由空气异常和布格重力异常。计算所得重力场的精度和分辨率大大高于常用的1∶140 0 0 0 0 0自由空气异常图及布格重力图     

河北张家口水泉沟岩体SHRIMP年代学研究及其意义

采用先进的 SHRIMP测年技术对河北水泉沟碱性杂岩体进行了年龄测定，获得东坪金矿区水泉沟岩体二长岩锆石 U- Pb年龄为 (390± 6)Ma，后沟金矿区水泉沟岩体正长岩年龄 (386± 6)Ma，比较可信地确定了水泉沟岩体的成岩时代为晚加里东期—早海西期。这表明北部温都尔庙-西拉木伦河加里东俯冲造山运动强烈地影响本区，水泉沟岩体是这次运动的产物。根据前人测得的东坪和后沟金矿床蚀变围岩钾长石的 Ar- Ar和 K- Ar年龄，金矿化的时代是中生代燕山期，与岩体的成岩年龄有 200 Ma的时差，成因上可能与碱性杂岩体关系不大，因此，东坪和后沟等金矿床可能不属于碱性岩型金矿床。     

块状硫化物矿石中硫化物的压溶和增生及成矿意义——以加拿大西部矿床为例

加拿大西部块状硫化物矿石普遍地发生过硫化物的压溶和增生。增生作用根据增生体的成分可以分为同质增生和异质增生，根据动力环境可以分为静态增生和动态增生。三晶嵌接结构可以是静态增生的产物。压溶和增生是块状硫化物矿床成岩和变质过程中的重要作用。脉石矿物的压溶可使原生矿石就地加富，硫化物的压溶可使成矿物质发生再活化。增生可促进矿质沉淀。富含硫化物的地层之所以能成为地球化学障而有利于后期热液叠加和层控矿床的形成，硫化物晶芽的增生是一种重要机制。     

中国西部地区物探工作的思考

中国西部地区地表条件恶劣,地下构造复杂矿产资源勘探的难度很大。要获得勘探的高效益,其中的一个核心问题是要做到物探先行。物探先行,不完全是一个勘探工作部署问题,要做到物探先行,必须解决好2个问题:一是思想认识上的问题;二是各种技术的难题。主要应包括如下5个方面:1.首先要有一种“知难而进”的精神,这是一种在诸多困难面前毫不气馁,奋发进取,迎难而上的精神,只有这样,才能把难题、难点找准,然后逐个突破,取得成功;2.要“有所为”和“有所不为”,这是辩证的统一,由于某些客观条件和主观能力的限制,我们只能在某些方面有所不为,才能在…     

由尔奈斯火山上的GEOSCOPE VBB台站得到的地倾斜信号

报道了距富尔奈斯火山顶8km处的GEOSCOPE台网甚宽频带地震台观测的甚长周期的瞬变过程。我们将地震台观测到的地面速度转换成地倾斜并通过与同一拱顶观测室内Blum型传统摆式倾斜仪记录的数据相比较检验了结果。通过比较表明，用水平地震仪测量周期小于25h的地倾斜是有效的。把这种方法用于1991年以来的几次火山喷发和岩浆侵入之前观测到的瞬变过程。由于GEOSCOPE台站到火山顶的距离适中，因而所得到的地倾斜观测值提供了有关火山喷发和岩浆侵入的信息，补充了火山顶部地倾斜观测网提供的有关岩浆源的形态和位置信息。     

TAKING INTO ACCOUNT THE EFFECT OF SECONDARY FLOWS IN DEPTH AVERAGED MORPHODYNAMIC SIMULATIONS

1 INTRODUCTIONThe numerical simulation of morphological changes in rivers, estuaries and coastal areas is because ofits econondcal merit an outstanding scientific task. The comPlexity of the problem is connected with theheterogeneity of the sediment material, an adequate rePresentation of the involved hydrOdynndc stressesand the large comPutational effort fOr long term simulations.Although the aPpllcation of three dimensional models tO engineering problems is increasing and wellvalldate…     

ON THE NUMBER OF FRACTIONS TO COMPUTE TRANSPORT OF SEDIMENT MIXTURES

1 INTRODUCTIONMany hydro-momhological mathematical models neglect the innuence of river bed maerialheterogeneity and its time and space changes during transport and related erosion/dePosition processes. Inthese models a rePresentative diameter of the river bed grain-size distribution (for examPle d5o) isspecified as initial data in each comPutational point of the modeled domain. Different d5o can be assignedto each ghd point but temPoral changes in bed material gradation cannot be simula…     

Ocean Ridge Granite and Its Geochemical Characteristics in Western Qinghai—Xizang Plateau

In our work,ocean ridge granite,i.e., Oytan plagiogranite massif,was discovered in western Qinghai-Xizang plateau.It intruded into the basic lava of the Oytag ophiolite suite and it was formed a little later than the (ultra)mafic rocks of the Oytag ophiolite suite.The Oytang plagiogranite possesses the geochemical characteristics of mantle-source granite and was formed in the “supre-subduction zone”(SSZ)ocean ridge environment,like the ocean ridge granite of Troodos,Cypus.     

Chemical Characteristics of Stream Draining fromDudu Glacier: An Alpine Meltwater Stream inGanga Headwater, Garhwal Himalaya

I-DtjcrONAlpine environment enjoys a distinct set of physicochemical conditions asl compared to other aqueous systems. Thehydrochemical characteristics of meltwater draining from thisenvironment are different from the other aqueous ecosystemsdue to their mountainous nature and extreme cold climatic conditions. The high concentration of various chemical constitu.ents in meltwater shows the intensive chemical weathering inthe basin. The rapid physical weathering due tO grinding actionof the gl…